SALT LAKE CITY - Emergency workers believe they have stopped a 21,000-gallon oil leak from reaching the environmentally sensitive Great Salt Lake, one of the West's most important inland water bodies for migratory birds that use it as a place to rest, eat and breed.

But the spill has taken a toll on wildlife at area creeks and ponds, coating about 300 birds with oil and possibly threatening an endangered fish.

The leak began Friday night when an underground pipeline broke in the mountains near the University of Utah. The breach sent oil into a creek that flows through neighborhoods, into a popular Salt Lake City park, and ultimately into the Jordan River, which flows into the Great Salt Lake.

The pipeline, owned by Chevron Corp., wasn't shut off until Saturday morning.

A spokesman for the Salt Lake City Joint Information Center, said yesterday emergency workers believe they have contained the spill to the Jordan River.

Still, the spill took its toll on birds at Red Butte Creek and at a large pond at Liberty Park, where visitors often feed birds from the shore and on rented paddle boats.